Jesus Camacho Rodriguez created HIVE-21267:
----------------------------------------------
Summary: Extend HiveRelColumnsAlignment to reorder group-by and
join keys on decreasing NDV automatically
Key: HIVE-21267
URL: https://issues.apache.org/jira/browse/HIVE-21267
Project: Hive
Issue Type: Improvement
Components: CBO
Reporter: Jesus Camacho Rodriguez
Assignee: Jesus Camacho Rodriguez
{{HiveRelColumnsAlignment}} was introduced to align the order of columns in
join, group-by, and order-by operators in the plan pipeline, trying to increase
the effect of ReduceDeduplication and thus reducing data shuffle.
The optimization could be extended to reorder group-by and join keys on
decreasing NDV, which would accelerate comparison runtime.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
